Milling cylinder block

Can anyone tell me how much can be milled off the cylinder for a 1980 KZ750 4 cylinder? Can I increase the base gasket size to off set this difference?

Thank You
Ray

i cant give u a # , but i can give u some info.
u need to measure the distance between the head and the pistons outer edge. the min gap on a kz900 and up is .040" for a street motor. this includes the base and head gasked after compresion.
why would u want to remove it from the top and add it back with a base gasket?
i have actualy done this in my current 1200cc motor.

Only reason I can think of is a warped firedeck?

Yeah something like that but not warped. Some reason the piston sleeve is lower on one piston and the machinist said it would need about 30 thousands taken off. The deck around this piston sleeve is slightly higher just enough to get a fingernail on it. I don't think it needs that much but the machinist thinks it does.

Funny thing about that cylinder is the sleeve on that one has these grooves in it but the other three are smooth. This is looking down at the top of the cylinder the walls on top of the sleeve have circular grooves on the top of the sleeve.

Try to send pics but this will be hard to see.

I just did this on my bike engine. My sleeves were sunk down .028" At first I thought it wasn't much. I could feel it with a finger nail. But when I actually measured it, it was .028" The machinist took off .030" to true it up. I recently had my head decked too and at that time he took off .006"
I ordered a .040" aluminum cylinder block spacer from ape to compensate for this. This is how I chose to fix the problem.

From APE:
KAWASAKI Z1900/KZ1000 / GPZ1100 thru '84
THICK PART# PRICE
.020" CYSPK020 $58.00
.040" CYSPK040 58.00
.063" CYSPK063 58.00
.080" CYSPK080 65.00
.125" CYSPK125 73.00

if the cyl is sunk, it will not seal properly.
u can take some material off, and replace it at the bottom with a shim.i dont use the base gasket in this circumstance.therefore i would add .020"(or what ever thickness the base gasket is , after compression) to the shim thickness to make up for the loss of base gasket.u dont need to come back up as high as the original block was , just as long as u have a min of .045" from head to block with all gaskets in, and after all gaskets are compressed.use Gaskasinch, or Copper kote on both sides of the shim.
before u start.
measure the current clearance.
put the old gaskets back in and re-torque the head(no cams).now put 2 pieces of solder in through #1,or 4 spark plug hole. hold the solder in place, over each wrist pin, AT the outer edge of the piston. now turn the crank over to compress the solder.now just measure the solder.Now u have a max clearance #. let us know what this # is.

to help clarify what mark is talking about.he is telling you to check the squish,which is the distance between the piston and the combustion chamber.
i am a translator from canadian to american :laugh: :silly: .

leon

The sleeve that is low was apparently changed in that block. The groove is because it was cut for an o'ring.

I would suggest replacing that sleeve with another smooth one. Be sure you press all of the sleeves down in a press before you surface it. If they are not seated, they will drop when the motor warms up and you will be right back where you are now.